1. Field of the Invention
This invention relates to a high efficiency encoding apparatus for compressing the input information by space-time sampling for transmitting the compressed information, and a high efficiency decoding apparatus for decoding the compressed information.
2. Description of the Related Art
There has recently been proposed in the U.S. Pat. No. 4,703,352 a high efficiency encoding/decoding apparatus in which data containing a large quantity of information, such as data of the picture information, is encoded by a transmitting side and transmitted at an increased rate, and in which data received by the receiving side is decoded for generating picture information having a picture quality close to that of the original transmitted picture.
In the high efficiency encoding/decoding method, the two-dimensional picture is sampled in a two-dimensional space or by a temporal-spatial sampling. The thinned or sub-sampled information is encoded for transmission. Among the examples of temporal-spatial sub-sampling is a so-called multiple sub-Nyquist sampling encoding system as proposed by Japan Broadcasting Corporation (NHK).
With the transmission by this method, the information is sub-sampled at the encoding time for transmission. The decoder interpolates the sub-sampled information based on the received information to re-construct the information. As a matter of fact, the decoding of the picture transmitted in this manner is by interpolation of the non-transmitted picture information by fixed taps and filters of fixed coefficients based on the transmitted information.
If, however, the decoding is performed at the decoding side by the above-described hardware configuration, picture reconstruction may or may not be achieved effectively by the interpolation depending on the widely variable type of picture information, such as a picture with motion or a still picture. As a matter of fact, the decoded picture exhibits various problems, such as blurring, jerkiness indicating non-spontaneous movement or time-space fluctuations such as movements in an object of a decoded picture.
In general, if a picture in which the effects of the interpolation cannot be effectively introduced by the above-described fixed filter configuration, the picture on the receiving side experiences the above-described problems which deteriorate the picture quality significantly.